The specific aims of this project are to determine whether dietary intervention decreases preference for high fat foods, and to determine whether this decreased preference is due to expected fat content rather than actual fat content of the foods. Lowering dietary fat intake in the population is one of the National Cancer Institute's goals for the year 2000. Taste is an important determinant of food selection, however, and in conditions of ad lib eating both animals and humans prefer foods containing high levels of fat over foods containing lower levels of fat. There is some evidence that people who have reduced their daily fat consumption report developing a reduced preference for high fat foods, and that this reported reduced preference is correlated with successful long term dietary change. This study will seek to identify the existence and mechanisms determining preference for fat in an intervention population which is reducing daily fat consumption. Subjects will be participants in the low fat dietary intervention trial of the Women's Health Initiative (WHI), called a Dietary Modification Trial in WHI. This clinical trial will randomize women into either an intervention trial to reduce daily fat consumption to 20 percent of daily calories or a control arm. A laboratory taste session will be conducted at baseline and six months after intervention begins. Subjects will be asked to taste either high fat milk drinks, or low fat milk drinks that contain a fat substitute. In order to assess the effect of labeling on preference, half of the subjects will be correctly informed about the fat content of the milk drink; the other half will receive incorrect information about the fat content. Preference will be assessed by self reports and by amount of drink consumed. We hypothesize that intervention participants will be more responsive to the label of high fat than to the actual fat content of the drink and will report a lower preference for both high fat and fat mimetic drinks than control participants when the drinks are labeled "high fat." These studies represent the first study of fat preference in a population currently participating in a randomized dietary intervention trial to reduce fat consumption by at least 50 percent. These findings have implications for the design of future dietary fat intervention trials, by emphasizing and encouraging decreased preferences for high fat foods.